js中实现高德地图坐标经纬度转百度地图坐标

1 function tobdMap(x, y) {
2                 var x_pi = 3.14159265358979324 * 3000.0 / 180.0;
3                 var z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * x_pi);
4                 var theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * x_pi);
5                 var bd_lon = z * Math.cos(theta) + 0.0065;
6                 var bd_lat = z * Math.sin(theta) + 0.006;
7                 var pt =new BMap.Point(bd_lon, bd_lat);
8                 return pt;
9             }